Not Applicable
Not Applicable
1. Field of the Invention
The present invention relates to a golf club head. More specifically, the present invention relates to a golf club head having a body with an annular deflection enhancement member for attachment of a striking plate thereto.
2. Description of the Related Art
When a golf club head strikes a golf ball, large impacts are produced that load the club head face and the golf ball. Most of the energy is transferred from the head to the golf ball, however, some energy is lost as a result of the collision. The golf ball is typically composed of polymer cover materials (such as ionomers) surrounding a rubber-like core. These softer polymer materials having damping (loss) properties that are strain and strain rate dependent which are on the order of 10-100 times larger than the damping properties of a metallic club face. Thus, during impact most of the energy is lost as a result of the high stresses and deformations of the golf ball (0.001 to 0.20 inches), as opposed to the small deformations of the metallic club face (0.025 to 0.050 inches). A more efficient energy transfer from the club head to the golf ball could lead to greater flight distances of the golf ball.
The generally accepted approach has been to increase the stiffness of the club head face to reduce metal or club head deformations. However, this leads to greater deformations in the golf ball, and thus increases in the energy transfer problem.
Some have recognized the problem and disclosed possible solutions. An example is Campau, U.S. Pat. No. 4,398,965, for a Method Of Making Iron Golf Clubs With Flexible Impact Surface, which discloses a club having a flexible and resilient face plate with a slot to allow for the flexing of the face plate. The face plate of Campau is composed of a ferrous material, such as stainless steel, and has a thickness in the range of 0.1 inches to 0.125 inches.
Another example is Eggiman, U.S. Pat. No. 5,863,261, for a Golf Club Head With Elastically Deforming Face And Back Plates, which discloses the use of a plurality of plates that act in concert to create a spring-like effect on a golf ball during impact. A fluid is disposed between at least two of the plates to act as a viscous coupler.
Yet another example is Jepson et al, U.S. Pat. No. 3,937,474, for a golf Club With A Polyurethane Insert. Jepson discloses that the polyurethane insert has a hardness between 40 and 75 shore D.
Still another example is Inamori, U.S. Pat. No. 3,975,023, for a Golf Club Head With Ceramic Face Plate, which discloses using a face plate composed of a ceramic material having a high energy transfer coefficient, although ceramics are usually harder materials. Chen et al., U.S. Pat. No. 5,743,813 for a Golf Club Head, discloses using multiple layers in the face to absorb the shock of the golf ball. One of the materials is a non-metal material.
Lu, U.S. Pat. No. 5,499,814, for a Hollow Club Head With Deflecting Insert Face Plate, discloses a reinforcing element composed of a plastic or aluminum alloy that allows for minor deflecting of the face plate which has a thickness ranging from 0.01 to 0.30 inches for a variety of materials including stainless steel, titanium, KEVLAR(copyright), and the like. Yet another Campau invention, U.S. Pat. No. 3,989,248, for a Golf Club Having Insert Capable Of Elastic Flexing, discloses a wood club composed of wood with a metal insert.
Although the prior art has disclosed many variations of golf club heads, the prior art has failed to provide a golf club head that increases the energy transfer from the golf club striking plate to the golf ball through increased deflection of a conventional striking plate.
The present invention provides a golf club head that is capable of imparting increased deflection of a striking plate composed of a rigid material during impact with a golf ball. The present invention is able to accomplish this by using an annular deflection enhancement member to isolate the striking plate from the body of the golf club head.
One aspect of the present invention is a golf club head including a body, a striking plate and an annular deflection enhancement member. The body has a hollow interior and a face opening thereto. The striking plate has an exterior surface and an interior surface. The annular deflection enhancement member is disposed between the body and the striking plate and isolates the striking plate from the body. The striking plate is composed of a first material and the annular deflection enhancement member is composed of a second material. The first material has a Young""s Modulus greater than that of the second material. Preferably, the Young""s Modulus of the second material is at least twenty-five percent lower than that of the first material. More preferably, the Young""s Modulus of the second material is at least fifty percent lower than that of the first material.
The striking plate may be composed of stainless steel and the second material may be titanium, titanium alloys, copper, aluminum, brass, magnesium, ceramics, composites or polymer materials. Alternatively, the striking plate may be composed of titanium, and the second material would then be composed of copper, aluminum, brass, magnesium, ceramics, composites or polymer materials. Yet further, the striking plate may be composed of an even softer material than titanium, and the second material would generally be a polymer material. The polymer materials would have a low dampening (loss) factor so that the deformation of the polymer doesn""t increase energy losses during impact with a golf ball.
The softer annular deflection enhancement member will reduce the stiffness of the striking plate. Thus, during impact with a golf ball, the striking plate will more easily deform or deflect, thus decreasing the deformation of the golf ball. Moreover, the contact time between the striking plate and the golf ball will increase thereby lowering the strain rate deformation of the golf ball. These factors will significantly decrease the energy lost during impact, or stated differently, these factors will increase the energy transfer from the golf club to the golf ball. The energy transfer will result in a golf club head having an increased coefficient of restitution. The coefficient of restitution is measured under test conditions, such as those specified by the USGA. The standard USGA conditions for measuring the coefficient of restitution is set forth in the USGA Procedure for Measuring the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Appendix II. Revision I, Aug. 4, 1998 and Revision 0, Jul. 6, 1998, available from the USGA.
Another aspect of the present invention is an iron golf club head. The iron golf club head has a body, a striking plate and an annular deflection enhancement member. The body has a shallow hollow interior and a face opening thereto. The striking plate has an exterior surface and an interior surface. The annular deflection enhancement member is disposed between the body and the striking plate, and isolates the striking plate from the body. The striking plate is composed of a first material and the annular deflection enhancement member is composed of a second material. The first material has a Young""s Modulus greater than that of the second material. Preferably, the Young""s Modulus of the second material is at least twenty-five percent lower than that of the first material. More preferably, the Young""s Modulus of the second material is at least fifty percent lower than that of the first material.
Yet another aspect of the present invention is a body, a striking plate and an deflection enhancement means having a Young""s modulus lower than that of the striking plate. The deflection enhancement means may be the material of the body modified from the rest of the body or a solder.
Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.